Hong Kong: With his baby face, eyeglasses and go-to outfit of T-shirt, jeans and sneakers, Jihan Wu looks more like a geeky teenager than a self-made billionaire. But thanks to an early foray into cryptocurrencies, the soft-spoken 32-year-old is sitting on what may be one of the industry’s largest fortunes.

Wu runs Bitmain Technologies Ltd, the world’s dominant producer of cryptocurrency mining chips. The Chinese company has been shrouded in secrecy since its founding five years ago, but Wu is gradually lifting the veil—and revealing clues about his personal wealth—as he pursues an expansion beyond the crypto-sphere that may eventually lead to an initial public offering.